Bug 2547

Summary:	Incorrect return from float nearbyint (0X1.3041C6P+21)
Product:	glibc	Reporter:	H.J. Lu <hjl.tools>
Component:	math	Assignee:	Andreas Jaeger <aj>
Status:	RESOLVED FIXED
Severity:	normal	CC:	drepper.fsp, glibc-bugs
Priority:	P2	Flags:	fweimer: security-
Version:	unspecified
Target Milestone:	---
Host:	x86_64-unknown-linux-gnu	Target:	x86_64-unknown-linux-gnu
Build:	x86_64-unknown-linux-gnu	Last reconfirmed:

Description H.J. Lu 2006-04-12 22:17:37 UTC

Failure: Test: nearbyint (0X1.3041C6P+21) == 0X1.3041C8P+21
Result:
 is:          2.49247200000000000000e+06   0x1.3041c000000000000000p+21
 should be:   2.49247300000000000000e+06   0x1.3041c800000000000000p+21
 difference:  1.00000000000000000000e+00   0x1.00000000000000000000p+0
 ulp       :  4.0000
 max.ulp   :  0.0000

Comment 1 H.J. Lu 2006-04-13 17:07:01 UTC

The problem is:

       The nearbyint() functions round their argument to an integer  value  in
       floating point format, using the current rounding direction and without
       raising the inexact exception.

But ieee754/flt-32/s_nearbyintf.c doesn't check the current rounding direction
at all.

Comment 2 Ulrich Drepper 2006-04-23 17:51:49 UTC

Suspended until somebody comes up with a patch.

Comment 3 Joseph Myers 2012-02-22 13:10:26 UTC

Fixed.

commit 6cbeae4719aeb3edb6143fe5dd6d2a5ab45c0248
Author: Joseph Myers <joseph@codesourcery.com>
Date:   Wed Feb 22 13:03:40 2012 +0000

    Fix nearbyintf rounding.